linux/fs/gfs2/recovery.c
Bob Peterson 623ba664b7 gfs2: When freezing gfs2, use GL_EXACT and not GL_NOCACHE
Before this patch, the freeze code in gfs2 specified GL_NOCACHE in
several places. That's wrong because we always want to know the state
of whether the file system is frozen.

There was also a problem with freeze/thaw transitioning the glock from
frozen (EX) to thawed (SH) because gfs2 will normally grant glocks in EX
to processes that request it in SH mode, unless GL_EXACT is specified.
Therefore, the freeze/thaw code, which tried to reacquire the glock in
SH mode would get the glock in EX mode, and miss the transition from EX
to SH. That made it think the thaw had completed normally, but since the
glock was still cached in EX, other nodes could not freeze again.

This patch removes the GL_NOCACHE flag to allow the freeze glock to be
cached. It also adds the GL_EXACT flag so the glock is fully transitioned
from EX to SH, thereby allowing future freeze operations.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-07-03 12:05:35 +02:00

475 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/crc32c.h>
#include <linux/ktime.h>
#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "glops.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "recovery.h"
#include "super.h"
#include "util.h"
#include "dir.h"
struct workqueue_struct *gfs_recovery_wq;
int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
struct buffer_head **bh)
{
struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
struct gfs2_glock *gl = ip->i_gl;
int new = 0;
u64 dblock;
u32 extlen;
int error;
error = gfs2_extent_map(&ip->i_inode, blk, &new, &dblock, &extlen);
if (error)
return error;
if (!dblock) {
gfs2_consist_inode(ip);
return -EIO;
}
*bh = gfs2_meta_ra(gl, dblock, extlen);
return error;
}
int gfs2_revoke_add(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
{
struct list_head *head = &jd->jd_revoke_list;
struct gfs2_revoke_replay *rr;
int found = 0;
list_for_each_entry(rr, head, rr_list) {
if (rr->rr_blkno == blkno) {
found = 1;
break;
}
}
if (found) {
rr->rr_where = where;
return 0;
}
rr = kmalloc(sizeof(struct gfs2_revoke_replay), GFP_NOFS);
if (!rr)
return -ENOMEM;
rr->rr_blkno = blkno;
rr->rr_where = where;
list_add(&rr->rr_list, head);
return 1;
}
int gfs2_revoke_check(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
{
struct gfs2_revoke_replay *rr;
int wrap, a, b, revoke;
int found = 0;
list_for_each_entry(rr, &jd->jd_revoke_list, rr_list) {
if (rr->rr_blkno == blkno) {
found = 1;
break;
}
}
if (!found)
return 0;
wrap = (rr->rr_where < jd->jd_replay_tail);
a = (jd->jd_replay_tail < where);
b = (where < rr->rr_where);
revoke = (wrap) ? (a || b) : (a && b);
return revoke;
}
void gfs2_revoke_clean(struct gfs2_jdesc *jd)
{
struct list_head *head = &jd->jd_revoke_list;
struct gfs2_revoke_replay *rr;
while (!list_empty(head)) {
rr = list_first_entry(head, struct gfs2_revoke_replay, rr_list);
list_del(&rr->rr_list);
kfree(rr);
}
}
int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,
unsigned int blkno, struct gfs2_log_header_host *head)
{
u32 hash, crc;
if (lh->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||
lh->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH) ||
(blkno && be32_to_cpu(lh->lh_blkno) != blkno))
return 1;
hash = crc32(~0, lh, LH_V1_SIZE - 4);
hash = ~crc32_le_shift(hash, 4); /* assume lh_hash is zero */
if (be32_to_cpu(lh->lh_hash) != hash)
return 1;
crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,
sdp->sd_sb.sb_bsize - LH_V1_SIZE - 4);
if ((lh->lh_crc != 0 && be32_to_cpu(lh->lh_crc) != crc))
return 1;
head->lh_sequence = be64_to_cpu(lh->lh_sequence);
head->lh_flags = be32_to_cpu(lh->lh_flags);
head->lh_tail = be32_to_cpu(lh->lh_tail);
head->lh_blkno = be32_to_cpu(lh->lh_blkno);
return 0;
}
/**
* get_log_header - read the log header for a given segment
* @jd: the journal
* @blk: the block to look at
* @lh: the log header to return
*
* Read the log header for a given segement in a given journal. Do a few
* sanity checks on it.
*
* Returns: 0 on success,
* 1 if the header was invalid or incomplete,
* errno on error
*/
static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
struct gfs2_log_header_host *head)
{
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
struct buffer_head *bh;
int error;
error = gfs2_replay_read_block(jd, blk, &bh);
if (error)
return error;
error = __get_log_header(sdp, (const struct gfs2_log_header *)bh->b_data,
blk, head);
brelse(bh);
return error;
}
/**
* foreach_descriptor - go through the active part of the log
* @jd: the journal
* @start: the first log header in the active region
* @end: the last log header (don't process the contents of this entry))
*
* Call a given function once for every log descriptor in the active
* portion of the log.
*
* Returns: errno
*/
static int foreach_descriptor(struct gfs2_jdesc *jd, u32 start,
unsigned int end, int pass)
{
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
struct buffer_head *bh;
struct gfs2_log_descriptor *ld;
int error = 0;
u32 length;
__be64 *ptr;
unsigned int offset = sizeof(struct gfs2_log_descriptor);
offset += sizeof(__be64) - 1;
offset &= ~(sizeof(__be64) - 1);
while (start != end) {
error = gfs2_replay_read_block(jd, start, &bh);
if (error)
return error;
if (gfs2_meta_check(sdp, bh)) {
brelse(bh);
return -EIO;
}
ld = (struct gfs2_log_descriptor *)bh->b_data;
length = be32_to_cpu(ld->ld_length);
if (be32_to_cpu(ld->ld_header.mh_type) == GFS2_METATYPE_LH) {
struct gfs2_log_header_host lh;
error = get_log_header(jd, start, &lh);
if (!error) {
gfs2_replay_incr_blk(jd, &start);
brelse(bh);
continue;
}
if (error == 1) {
gfs2_consist_inode(GFS2_I(jd->jd_inode));
error = -EIO;
}
brelse(bh);
return error;
} else if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LD)) {
brelse(bh);
return -EIO;
}
ptr = (__be64 *)(bh->b_data + offset);
error = lops_scan_elements(jd, start, ld, ptr, pass);
if (error) {
brelse(bh);
return error;
}
while (length--)
gfs2_replay_incr_blk(jd, &start);
brelse(bh);
}
return 0;
}
/**
* clean_journal - mark a dirty journal as being clean
* @jd: the journal
* @head: the head journal to start from
*
* Returns: errno
*/
static void clean_journal(struct gfs2_jdesc *jd,
struct gfs2_log_header_host *head)
{
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
u32 lblock = head->lh_blkno;
gfs2_replay_incr_blk(jd, &lblock);
gfs2_write_log_header(sdp, jd, head->lh_sequence + 1, 0, lblock,
GFS2_LOG_HEAD_UNMOUNT | GFS2_LOG_HEAD_RECOVERY,
REQ_PREFLUSH | REQ_FUA | REQ_META | REQ_SYNC);
if (jd->jd_jid == sdp->sd_lockstruct.ls_jid) {
sdp->sd_log_flush_head = lblock;
gfs2_log_incr_head(sdp);
}
}
static void gfs2_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
unsigned int message)
{
char env_jid[20];
char env_status[20];
char *envp[] = { env_jid, env_status, NULL };
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
ls->ls_recover_jid_done = jid;
ls->ls_recover_jid_status = message;
sprintf(env_jid, "JID=%u", jid);
sprintf(env_status, "RECOVERY=%s",
message == LM_RD_SUCCESS ? "Done" : "Failed");
kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);
if (sdp->sd_lockstruct.ls_ops->lm_recovery_result)
sdp->sd_lockstruct.ls_ops->lm_recovery_result(sdp, jid, message);
}
void gfs2_recover_func(struct work_struct *work)
{
struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
struct gfs2_log_header_host head;
struct gfs2_holder j_gh, ji_gh, thaw_gh;
ktime_t t_start, t_jlck, t_jhd, t_tlck, t_rep;
int ro = 0;
unsigned int pass;
int error = 0;
int jlocked = 0;
if (gfs2_withdrawn(sdp)) {
fs_err(sdp, "jid=%u: Recovery not attempted due to withdraw.\n",
jd->jd_jid);
goto fail;
}
t_start = ktime_get();
if (sdp->sd_args.ar_spectator)
goto fail;
if (jd->jd_jid != sdp->sd_lockstruct.ls_jid) {
fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n",
jd->jd_jid);
jlocked = 1;
/* Acquire the journal lock so we can do recovery */
error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
LM_ST_EXCLUSIVE,
LM_FLAG_NOEXP | LM_FLAG_TRY | GL_NOCACHE,
&j_gh);
switch (error) {
case 0:
break;
case GLR_TRYFAILED:
fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
error = 0;
default:
goto fail;
}
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
LM_FLAG_NOEXP | GL_NOCACHE, &ji_gh);
if (error)
goto fail_gunlock_j;
} else {
fs_info(sdp, "jid=%u, already locked for use\n", jd->jd_jid);
}
t_jlck = ktime_get();
fs_info(sdp, "jid=%u: Looking at journal...\n", jd->jd_jid);
error = gfs2_jdesc_check(jd);
if (error)
goto fail_gunlock_ji;
error = gfs2_find_jhead(jd, &head, true);
if (error)
goto fail_gunlock_ji;
t_jhd = ktime_get();
fs_info(sdp, "jid=%u: Journal head lookup took %lldms\n", jd->jd_jid,
ktime_ms_delta(t_jhd, t_jlck));
if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
fs_info(sdp, "jid=%u: Acquiring the transaction lock...\n",
jd->jd_jid);
/* Acquire a shared hold on the freeze lock */
error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
LM_FLAG_NOEXP | LM_FLAG_PRIORITY |
GL_EXACT, &thaw_gh);
if (error)
goto fail_gunlock_ji;
if (test_bit(SDF_RORECOVERY, &sdp->sd_flags)) {
ro = 1;
} else if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
ro = 1;
} else {
if (sb_rdonly(sdp->sd_vfs)) {
/* check if device itself is read-only */
ro = bdev_read_only(sdp->sd_vfs->s_bdev);
if (!ro) {
fs_info(sdp, "recovery required on "
"read-only filesystem.\n");
fs_info(sdp, "write access will be "
"enabled during recovery.\n");
}
}
}
if (ro) {
fs_warn(sdp, "jid=%u: Can't replay: read-only block "
"device\n", jd->jd_jid);
error = -EROFS;
goto fail_gunlock_thaw;
}
t_tlck = ktime_get();
fs_info(sdp, "jid=%u: Replaying journal...0x%x to 0x%x\n",
jd->jd_jid, head.lh_tail, head.lh_blkno);
/* We take the sd_log_flush_lock here primarily to prevent log
* flushes and simultaneous journal replays from stomping on
* each other wrt sd_log_bio. */
down_read(&sdp->sd_log_flush_lock);
for (pass = 0; pass < 2; pass++) {
lops_before_scan(jd, &head, pass);
error = foreach_descriptor(jd, head.lh_tail,
head.lh_blkno, pass);
lops_after_scan(jd, error, pass);
if (error)
goto fail_gunlock_thaw;
}
clean_journal(jd, &head);
up_read(&sdp->sd_log_flush_lock);
gfs2_glock_dq_uninit(&thaw_gh);
t_rep = ktime_get();
fs_info(sdp, "jid=%u: Journal replayed in %lldms [jlck:%lldms, "
"jhead:%lldms, tlck:%lldms, replay:%lldms]\n",
jd->jd_jid, ktime_ms_delta(t_rep, t_start),
ktime_ms_delta(t_jlck, t_start),
ktime_ms_delta(t_jhd, t_jlck),
ktime_ms_delta(t_tlck, t_jhd),
ktime_ms_delta(t_rep, t_tlck));
}
gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);
if (jlocked) {
gfs2_glock_dq_uninit(&ji_gh);
gfs2_glock_dq_uninit(&j_gh);
}
fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
goto done;
fail_gunlock_thaw:
gfs2_glock_dq_uninit(&thaw_gh);
fail_gunlock_ji:
if (jlocked) {
gfs2_glock_dq_uninit(&ji_gh);
fail_gunlock_j:
gfs2_glock_dq_uninit(&j_gh);
}
fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
fail:
jd->jd_recover_error = error;
gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
done:
clear_bit(JDF_RECOVERY, &jd->jd_flags);
smp_mb__after_atomic();
wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
}
int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
{
int rv;
if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
return -EBUSY;
/* we have JDF_RECOVERY, queue should always succeed */
rv = queue_work(gfs_recovery_wq, &jd->jd_work);
BUG_ON(!rv);
if (wait)
wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
TASK_UNINTERRUPTIBLE);
return wait ? jd->jd_recover_error : 0;
}